Gas burner



Jan. 16, E H HSHER I I 1,943,859-

GAS BURNER Filed April 19, 1933 WITNESSES INVENTOR W. 22w; 1/ $4756,.Z/n. 34w q 5 a a/410* 40:

i; MM;

Patented Jan. 16, 1934 4 UNITED STATES PATENT OFFICE GAS BURNERApplication April 19, 1933.

3 Claims.

This invention relates to gas burners, and more especially to laboratoryburners of the so-called Bunsen type.

Various embodiments of the Bunsen labora- 5 tory burner are made whichoperate satisfactorily with manufactured gas to produce flames ofdifferent character, e. g., oxidizing or reducing.

Natural gas, however, requires larger amounts of air for combustion thanmanufactured gas, and in consequence the ordinary forms of Bunsen burnerdo not operate satisfactorily with it. A

common experience is that the flame is extinguished readily byextraneous air currents, particularly when the air supply is regulatedto give an oxidizing flame.

Various means have been proposed for adapting such burners to use withnatural gas, but so far as I am aware all of them have been subject todisadvantages of one kind or another. For instance, some of these meansare not practically operative, while others are not mechanicallysatisfactory or are expensive to make.

It is among the objects of this invention to provide a Bunsen typelaboratory gas burner with means adapting it to satisfactory use withnatural gas, which means are of simple and inexpensive construction, maybe embodied as an integral part of a burner or supplied as an accessoryfor use with ordinary laboratory burners, and which in the preferredembodiment eliminate back firing.

The invention may be described in connection with the accompanyingdrawing, which represents its preferred embodiment, and in which Fig. 1is a vertical elevation of an ordinary type of burner provided with atip embodying the invention; Fig. 2 a longitudinal sectional view, on anenlarged scale, through the tip shown in Fig. 1, taken on line II-IIthereof; and Fig. 3 a plan view of the tip shown in Fig. 2.

The invention contemplates Bunsen type laboratory burners including aburner barrel, or tube, provided at the lower end with means forintroducing a mixture of gas and air, and having I its upper portion ofsubstantially uniform diameter. In accordance with the invention theupper end of the barrel is provided with a tubular tip having a borewhose lower portion is of substantially the same diameter as the bore ofthe barrel, the upper portion of the bore being of reduced diameter.Surrounding the tip bore is an annular chamber of increasing volumeupwardly, the lower portion of the chamber communicating with the lowerportion of the tip bore by perforations formed in its wall. The lowerend of the chamber is closed, and the upper end is defined by Serial No.666,855

a wall provided with a plurality of perforations surrounding the tip.

In the use of a burner tipped in accordance with the invention a slightback pressure is created in the lower portion of the tip in consequenceof the reduction in bore diameter at the upper end. This causes a smallamount of the gas-air mixture flowing through the burner to expandthrough the perforations into the annular chamber, and this lay-passedgas further expands within the annular chamber by reason of itsconstruction, so that the gas escaping through the perforations in thetop of the chamber provides a low velocity pilot flame surrounding themain, high velocity mixture of gas and air flowing through the tip bore.This pilot flame successfully maintains the main flame ignited under allconditions of use with natural gas.

The invention may be described more in detail with reference to thedrawing. Fig. 1 shows a conventional type of laboratory Bunsen burnercomprising a base 1 supporting a burner barrel 2 provided at its lowerend with a nipple 3 for connection to a source of gas and leading to anozzle, not shown, within the barrel. The lower end of the barrel issurrounded by a rotatable sleeve 4 having perforations 5 adapted to bebrought into regulated register with perforation 6 in the barrel, so asto control the amount of air drawn into the barrel by the flow of gasthrough the nozzle. Various forms of gas nozzle and air-regulating meansother than those shown are known in the art, the form shown beingconventionally represented for purposes of illustration.

The burner shown in Fig. 1 is of a type commonly used satisfactorilywith manufactured gas. The upper end of barrel 2, which is ofsubstantially uniform diameter, is provided with a removable tip 7 whichin accordance with the invention comprises a tubular member 8 having acentral bore having lower, intermediate and upper portions ofsuccessively progressively reduced diameter. Lower portion 9 of the boreis of substantially the outer diameter of barrel 2, as shown in Fig. 2,so as to neatly lit the top of 100 barrel 2. The diameter ofintermediate portion 10 is reduced so that it is substantially the sameas the bore of barrel 2, and upper portion 11 of the tip bore is ofstill further reduced diameter. portions of the bore is an annularexpansion chamber which is connected near its bottom to intermediateportion 10 of the bore by perforations 12 formed in its wall.

These tips may be, and preferably are, made Surrounding the intermediateand upper v sizes smaller.

by machining a brass, or other suitable metal, rod or tube ofappropriate diameter. Most suitably the annular expansion chamber isformed by cutting recesses 13 and 14 to provide recesses annularlysurrounding the intermediate and upper portions of the bore. Recess 14is of greater volume than recess 13 and it is cut to provide a topflange 15. Preferably the recesses are cut to leave an intermediateflange l6 separating them approximately in the plane betweenintermediate bore portion 10 and upper portion 11, for a purposepresently to be described. Flanges 15 and 16 are drilled to provideperforations 17 and 18, respectively, for flow of gas through and outfrom the chamber.

The annular chamber is closed by a side wall casing member comprising asection of tubing 19 whose inner diameter is such as to snugly engageflanges 15 and 16, to prevent leakage of gas between the flanges and thecasing. The lower end of casing 19 is rolled or crimped into a groove inthe body of the tip, as indicated at 20, Fig. 2, to close the lower endof the chamber.

In the use of this burner tip a mixture of gas and air flows upwardlythrough the burner barrel and emerges into the intermediate portion ofthe tip, flowing thence through the upper portion of the tip and leavingthe tip through upper bore portion 11. The reduction in diameter of theupper portion of the tip creates a slight back pressure in theintermediate portion, which causes a small amount of gas to expandthrough perforations 12 into the bottom portion of the annular chamber,from whence it flows upwardly through the chamber, expandingprogressively,

so that it emerges through perforations 1'? in a plurality of lowvelocity jets which form a pilot flame surrounding the bore. Thisring-lil e pilot flame remains lighted, because due to its low verlocity it is not affected by air currents, so that it maintains the mainflame issuing from the upper portion 11 of the tip bore ignited despiteany tendency for it to be extinguished.

A particular feature of the invention resides in making perforations 18somewhat smaller than perforations 17, which eliminates any tendency toback-fire through the lower portion of the annular chamber into theburner barrel, to cause base burning. For example, with a tip having aan outside diameter of inch at its upper end,

and having upper bore portion 11 of g t inch diameter, perforations 17may be made with a No. 45 twist drill, the holes being spaced 60 apart.Perforations 18 may be made with a drill a few Perforations 12 may berelatively large, for example, No. 28 drill size, only two of them beingrequired, and because of the back pressure in the bore they need not beinclined upwardly or provided with gas-deflecting baffles, but

i :may be horizontal, as shown.

stood that, if desired, the tip can be embodied as an integral part of aburner, for example in the case of burners intended for use with naturalgas alone.

According to the provisions of the patent statutes, I have explained theprinciple and construc tion of my invention and have illustrated anddescribed what I now consider to represent its best embodiment. However,I desire to have it understood that, within the scope of the appendedclaims, the invention may be practiced otherwise than as specificallyillustrated and described.

I claim:

1. A detachable adapter tip for a laboratory gas burner comprising atubular member having its bore composed of lower, intermediate and upperportions of successively reduced diameter upwardly from the base of thetip, the diameters of said lower and intermediate portions being,respectively, substantially those of the exterior and interior diametersof the burner barrel to which the tip is applied, an expansion chamberclosed at its lower end surrounding said intermediate and upperportions, the lower end of the chamber being smaller than the upper endand being connected to said intermediate bore portion by perforationsthrough the wall, and the top of said expansion chamber being providedWith a top wall having a plurality of perforations surrounding saidupper bore portion.

2. A detachable burner tip for a laboratory gas burner comprising atubular member having its. bore composed of lower, intermediate andupper portions of successively reduced diameter up-,

intermediate bore portion by perforations through i the wall, and theupper portion of said expansion chamber being provided with a top wallhaving a plurality of perforations surrounding the upper end of the tip.

3. A detachable adapter tip for a laboratory gas burner comprising atubular metallic sleeve having inwardly projecting shoulders forming abore comprising, respectively, a lower portion adapted to neatly receivethe top of the burner barrel, an intermediate portion of substantiallythe interior diameter of the barrel, and an upper portion of furtherreduced diameter, the exterior of the sleeve being recessed peripherallyto provide a top flange and a second flange disposed approximately in aplane between said upper and intermediate bore portions, and a casingmember disposed in contact with said flanges and forming therewith alower chamber annular to said intermediate portion and upper chamber ofgreater volume annular to said upper bore portion, said top flange beingprovided with perforations surrounding the tip, and said second flangebeing provided with perforations smaller than those in said top flange,and the wall of said intermediate bore portion being perforated for flowof gas into said lower chamber under back pressure in said intermediatebore portion caused by said upper bore portion.

EDWIN H. FISHER.

